5.28.2 API

Returns a string describing the jepg. This is a very short description,
use it for logs, and to debug stuff. By no means it’s a complete exhaustive
description. Still, the string returned should be unique.

Creates a JPEG screenshot from a game state. The user_dir parameter
is used to build a file name and then use it
to write data on disk, it is then read and kept in memory.
Globally it’s not that bad to store it for we do not generate
screenshots that often, and it’s nice for debugging to have it so
developping a RAM-only writer wouldn’t make it a blast anyway.